<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>示例1</title>
    <style>

        .box {
            border: 1px solid red;
            height: 300px;
            display: flex;
        }
        .box div{
            border: 1px solid blue;
        }

        .box .box1{
            width: 200px;
            height: 300px;
        }
        .box .box2{
            /* flex-grow: 1; */
            flex:1;
        }
    </style>
</head>

<body>
    <div class="box">
        <div class="box1">左边固定</div>
        <div class="box2">右边自适应</div>
    </div>
</body>

</html>